Water-cooled dental cutting member and handpiece for use therewith

ABSTRACT

A WATER-COOLED DENTAL CUTTING MEMBER THAT MAY BE USED FOR CUTTING, GRINDING, OR DRILLING, DEPENDING UPON THE CONFIGURATION OF THE TOOTH-CONTACTING PORTION THEREOF, AND A TURBINE-TYPE DENTAL HANDPIECE THAT IS PARTICULARLY ADAPTED FOR REMOVABLY SUPPORTING THE CUTTING MEMBER, AS WELL AS SUPPLYING A CONSTANT FLOW OF COOLING WATER THERETO. THE TURBINE ROTOR IN THE HANDPIECE OPERATES WITHIN A CONFINED SPACE THAT IS AT A SUBSTANTIALLY HIGHER AIR PRESSURE THAN THE PRESSURE OF THE COOLING WATER. ACCORDDINGLY, COOLING WATER HAS NO TENDENCY TO ENTER THAT PORTION OF THE HANDPIECE IN WHICH THE ROTOR IS SUPPORTED TO SLOW DOWN THE RATE OF ROTATION OF THE ROTOR OR STOP THE ROTOR BY FRICTIONAL CONTACT THEREWITH.

Dec. 7, 1971 J. B. BARSBY 3,624,905

WATER-COOLED DENTAL CUTTING MEMBER AND HANDPIECE FOR USE THEREWITH Filed Feb. 4, 1970 IN VEN TOR. JQMEJ B. Baasay flrraexvay United States Patent Oflice Patented Dec. 7, 1971 3,624,905 WATER-COOLED DENTAL CUTTING MEMBER AND HANDPIECE FOR USE THEREWITH James B. Barsby, 6477 Atlantic Ave., Long Beach, Calif. 90805 Filed Feb. 4, 1970, Ser. No. 8,639 Int. Cl. A61c 1/10 US. Cl. 3227 3 Claims ABSTRACT OF THE DISCLOSURE A water-cooled dental cutting member that may be used for cutting, grinding, or drilling, depending upon the configuration of the tooth-contacting portion thereof, and a turbine-type dental handpiece that is particularly adapted for removably supporting the cutting member, as well as supplying a constant flow of cooling water thereto. The turbine rotor in the handpiece operates within a confined space that is at a substantially higher air pressure than the pressure of the cooling water. Accordingly, cooling water has no tendency to enter that portion of the handpiece in which the rotor is supported to slow down the rate of rotation of the rotor or stop the rotor by frictional contact therewith.

BACKGROUND OF THE INVENTION Field of the invention A water-cooled dental cutting member and handpiece for use therewith.

Description of the prior art Turbine type dental handpieces have been used for a number of years to drive cutting members used for drilling and grinding by abrasive frictional contact with a tooth, contact generates heat that is most uncomfortable to a patient. To alleviate the discomfort of the heat so generated, the dentist intermittently conducts the cutting, grinding or drilling operations.

Numerous attempts have been made in the past to provide a dental handpiece that would drive a cutting member at high speed and also water-cool the latter as well as that portion of the tooth with which the member is in functional contact. These attempts have not been successful, for in the prior handpieces the cooling water has a tendency to ultimately flow into the portion of the handpiece in which the rotor is supported, which slows down the rate of rotation of the rotor by frictional contact therewith. The purpose of the present invention is to supply a water-cooled dental cutting member and handpiece for use therewith that is free of the operational disadvantages found in prior art devices of this nature.

SUMMARY OF THE INVENTION A water-cooled rotatable dental cutting member that includes a shank and a cutting body supported from a first end thereof. A transverse water passage is formed in the shank that is in communication with a longitudinal passage extending at least through the cutting body. Although the operational portion of the dental cutting member is hereinafter referred to as a cutting body, it may serve not only this function, but may also be used for drilling or grinding. The shape of the cutting body will, of course, determine the function that it is most suited for.

The dental cutting member is rotated by a turbine-type dental handpiece that includes a recessed turbine rotor which frictionally and removably engages the cutting member. Water is supplied to a confined space in the handpiece that is in communication with said transverse passage. The interior portion of the handpiece in which the rotor is supported is in communication with an air discharge member and a pressurized air inlet member. The air pressure in the portion of the handpiece in which the rotor is supported is higher than that of the cooling water in the confined space, whereby there is no tendency for water to contact the rotor and slow the rotation thereof or stop the same. Water flows from the confined space into the cutting member to discharge therefrom and cool the cutting body, together with the portion of a patients tooth with which it is in rotational frictional contact.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of the handpiece and the water-cooled cutting member;

FIG. 2 is a longitudinal cross-sectional view of the head portion of the device;

FIG. 3 is a transverse cross-sectional view of the device taken on the line 33 of FIG. 2;

FIG. 4 is a second longitudinal cross-sectional view of the head portion, but with the cutting member removed therefrom;

FIG. 5 is a perspective view of the cutting member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The water-cooled cutting member A, as may best be seen in FIGS. 1 and 2, is adapted to be removably supported in a turbine-type dental handpiece B.

Cutting member A includes an elongate shank 10, and a cutting body 12 is supported on a first end portion 14 thereof. The shank 10 and cutting body 12 are preferably formed as an integral unit from a single body of metallic material such as high speed steel, or the like. A first longitudinal passage 16 is formed in shank 10 and intersects a second transverse passage 18 also formed in the shank. A third longitudinal passage 20 is formed in cutting body 12, is axially aligned with first passage 16, and in communication therewith.

The dental handpiece B, as may be seen in FIG. 1 includes a tubular elongate barrel assembly 22 that serves as a grip for manipulating the head 24 that rotatably supports cutting member A. Head 24 includes a cylindrical shell 26 having a tapped first end 28 and a second closed end portion 30. First end 28 is sealingly and threadedly engaged by an externally threaded end piece 32, which end piece cooperates with a shell 26 to define a first confined space 34. A second transverse confined space 36 is provided in the second closed end portion 30.

A cylindrical plug 38 extends outwardly from one side of shell 26, which plug removably and slidably engages a second cylindrical shell 40 (FIGS. 1 and 2) that forms a part of the barrel assembly 22. Second shell 40 is connected on its free end to a flexible conduit (not shown) as is conventional with dental handpieces.

First and second longitudinally spaced ball bearing assemblies 42, are mounted in the confined space 34 of shell 26. Each assembly 42 includes inner and outer races 44 and 46, respectively, in which races a number of circumferentially arranged ball bearings 47 disposed therebetween. The inner races 44 frictionally engage the end portions 45 of a turbine rotor 48. Rotor 48, as illustrated in FIG. 2, has three longitudinally spaced circular blades 50 projecting outwardly therefrom.

An air inlet passage 52 extends longitudinally through plug 38, and is connected on a first end portion 54 thereof to a conduit 56. The conduit 56 is connected to a source of air under pressure (not shown). Air inlet passage 52 is of greater diameter than the width of the center blade 50 with which it is aligned as shown in FIG. 2.

Air from inlet passage 52 discharges on to rotor 48 on both sides of the center blade 50, and causes rotation of the rotor, due to frictional contact with the center blade and the two blades 50 on each side thereof. Air in first confined space 34, after frictional contact with the blades 50 is discharged through two passages 58- in plug 38 that are in communication with the interior of the second shell 40 (FIG. 2). The interior of shell 40 is in communication with the ambient atmosphere by conventional means (not shown).

The end portion 45 of rotor 48 closest to second end portion 30, as may best be seen in FIG. 4, is provided with two transversely aligned bores 60 that are in communication with a longitudinal recess 62 formed in rotor 4-8. Recess 62 is of such transverse cross section as to snugly and slidably engage shank of cutting member A. Two resilient cylindrical plugs 64 are positioned in bores 60 and extend slightly into recess 62. The outer ends of plugs 64 abut against the inner race 44 most adjacent thereto. The portions of plugs 64 projecting into recess 62 are of slightly convex configuration. Plugs 64 frictionally engage shank 10, and serve to removably support cutting member A from rotor 48. Plugs 64 are preferably formed from nylon, or like material.

A bore 66 is formed in the second closed end 30, and is in axial alignment with recess 62, and is also in communication with second confined space 36. When cutting member A is mounted in dental handpiece B (FIG. 1), the shank 10 is disposed in recess 62 and bore 66, with second passage 18 being in communication with second confined space 36.

A recess 68 is formed in second closed end 30, and is in longitudinal alignment with the second confined space 36. Recess 68 supports a resilient tube 70 through which a bore 72 extends. A first end portion of a water supply line 74 is in sealing engagement with bore 72, as may be seen in FIG. 4. The water supply line 74 extends longitudinally along the dental handpiece B as shown in FIG. 2, and is connected to a source of water under pressure (not shown).

In use, operation of the invention is relatively simple. One of the cutting members A is mounted in the dental handpiece B in the manner shown in FIG. 2. Air under pressure is caused to discharge through conduit 56 to drive rotor 48. Water under pressure is caused to discharge through line 74 into second confined space 36, from which the water flows through first, second, and third passages 16, 18, and 20 to discharge onto that portion of the tooth (not shown) being cut, drilled or ground by the rotating body 12. The discharging water not only cools the body 12, but the surface of the tooth (not shown) with which the body 12 is in frictional cutting contact.

To prevent water in second confined space 36 from migrating into first confined space 34 and stopping or slowing down the rate of rotation of rotor 48, the air pressure in first confined space 34 should be maintained at a substantially higher than the pressure of the cooling water in second confined space 36.

I claim:

1. An air driven, water-cooled dental cutting assembly that includes:

(a) an elongate rigid shank that supports a cutting member in the form of a surface of revolution from a first end thereof, said shank having a transverse bore therein intermediate said surface of revolution and a second end of said shank, and said transverse bore in communication with a longitudinal passage in said shank that extends through said surface of revolution;

(b) a rotor having a longitudinal opening therein that frictionally and removably receives said shank;

(c) a pair of spaced bearings that frictionally engage end portions of said rotor;

(d) a head that includes a cylindrical shell and first and second end pieces, said head defining a first confined space in which said bearings are disposed to rotatably support said rotor, with said shank extending outwardly through a longitudinal bore in said second end piece, and said second end piece having a transverse cavity therein that intersects said bore and is in communication with said transverse bore in said shank;

(e) a cylindrical plug that supports said head from a first end thereof, said plug having at least one first and one second longitudinal passage therein that are in communication with said first confined space, with said first passage serving to have compressed air discharged therethrough at a first pressure to impinge on said rotor to rotate the latter and said shank and cutting member, and said second passage permitting air to escape therefrom to the ambient atmosphere after rotating said rotor; and

(f) first meansfor discharging water to said cavity in said second end piece at a second pressure less than that of said first pressure to flow through said transverse bore in said shank and said longitudinal passage in said shank and cutting member to cool said cutting member and the body said cutting member is cutting, with said flow of water not impeding the rate of rotation of said rotor by frictional contact therewith due to said air at said first pressure preventing water at said second pressure entering said first confined space.

2. A dental cutting assembly as defined in claim 1 in which each of said bearings is a ball bearing assembly that includes inner and outer races, with said inner races frictionally engaging end portions of said rotors to rotatably support said rotor relative to said head, and said outer races occupying fixed positions in said first confined space.

3. A dental cutting assembly as defined in claim 2 in which a first end of said cylindrical shell is open and said shell has threads formed on the interior surface thereof adjacent said open end, and said first end piece is an externally threaded member that removably engages said threads on said internal surface.

References Cited UNITED STATES PATENTS ROBERT PESHOCK, Primary Examiner U.S. Cl. X.R. 

